There are many methods for manufacturing optoelectronic assemblies that include integrated optical and electrical devices and components on a substrate. The optical and electrical devices and components may be among others optical fibers, lenses, mirrors, light emitting diodes, laser diodes, photodiodes, detectors, semiconductor devices, capacitors, inductors and resistors.
Several prior art methods utilise silicon “V-grooves” as fiber positioning elements. U.S. Pat. No. 4,767,174 makes use of the fact that certain crystalline orientations of silicon substrates can be preferentially etched to a high degree of accuracy. This is accomplished by a series of lithographic steps including resist coating and exposure, followed by liquid etching. This is an expensive method, which is not compatible with standard microelectronic infrastructures and processes.
Alternatively, the V-groove and optical fiber can be positioned relative to a waveguide by using additional positioning elements. These positioning elements also increase the complexity and cost of the method. Even when the V-groove technique is utilised only to couple two optical fibers to one another, as in U.S. Pat. No. 4,973,126, there are several additional positioning elements required.
U.S. Pat. No. 4,735,677 describes a method for providing guides for aligning optical fibers on the surface of a silicon substrate. In this method it is necessary to first grow a layer of glass on the silicon wafer by a soot process. This layer of glass is then lithographically patterned and etched, as by reactive ion etching (RIE), to form the positioning elements. After formation of these elements, an optical fiber can be inserted between them and fixing is accomplished with an adhesive or by melting the glass with a CO.sub.2 laser beam. This technique involves a great number of processing steps and is limited to substrates that are not damaged by high temperature processes or those that do not contain sensitive electronic devices that would be damaged by an RIE etch.
U.S. Pat. No. 4,750,799 teaches a hybrid optical integrated circuit having a high-silica glass optical waveguide formed on a silicon substrate, an optical fiber and an optical device coupled optically to the optical waveguide, and an optical fiber guide and an optical device guide on the substrate for aligning the optical fiber and the optical device at predetermining positions, respectively, relative to the optical waveguide. Islands carrying electrical conductors are disposed on the substrate, a first electrical conductor film is formed on the substrate, second electrical conductor films are formed on the top surfaces of the optical waveguide, the optical fiber guide, the optical device guide and the islands and are electrically isolated from the first electrical conductor film.
U.S. Pat. No. 4,796,975 teaches a method of aligning and attaching optical fibers to substrate optical waveguides. One or more slabs of preferentially etchable material and a waveguide substrate are placed adjacent to each other face down on a flat surface for aligning the tops of the slabs with the top of the waveguide. A backing plate is secured to the back surface to hold the entire assembly together. The preferentially etchable material is etched to form V-grooves in alignment with the light guiding region of the waveguide substrate. Optical fibers are secured within the groove and are optically aligned with the light guiding region.
U.S. Pat. No. 5,359,687 teaches an optical coupling device having a substrate with a surface region at a pre-determined position on the surface of the substrate for placing an optical waveguide. The substrate further includes a channel on its surface for optically aligning and coupling an optical fiber to an optical waveguide positioned at the predetermined position. The longitudinal axis of the channel is in alignment with the predetermined position such that on placement of the optical fiber in the channel and placement of the optical waveguide in the position the light carrying core of the fiber and the waveguide are substantially in optical alignment.
U.S. Pat. No. 6,266,472 describes a process of splicing optical fibers having of a substrate and at least one optical fiber gripper on the substrate. The gripper includes adjacent parallel, polymeric strips each having a base attached to a surface of the substrate, a top surface in a plane parallel to the substrate, and side walls, which form a groove between adjacent strips. The invention provides strips of polymeric splice elements, also known as elastomeric polymer grippers, to provide a splice means for optical fibers. Once these grippers are deposited on a substrate, optical fibers can be snapped between them. The splicing elements allow for accurate lateral and longitudinal alignment and improved collinearity of spliced optical fibers, achieving low coupling loss.
U.S. Pat. No. 6,371,655 provides a molded plastic housing that incorporates a device and other optical elements including an optical fiber and lenses. The device may be a transmitter. The entire housing assembly may be connected to another similar assembly housing a receiver. The transmitter package may be mounted side-by side in another plastic housing.
U.S. Pat. No. 6,285,808 and U.S. Pat. No. 6,324,328 provide a circuit carrier having an optical polymer layer embedded between layers of insulating or conducting materials. The circuit carrier structure including the optical layer is formed by conventional laminating processes.
U.S. Pat. No. 6,376,268 provides an optoelectronic assembly having an insulating substrate with a planar surface and a metal layer bonded to the planar surface. The metal layer is patterned and adapted to receive active and passive optical components. Structures formed in the metal layer (i.e., steps) are utilized as fiduciaries for positioning of the optical components. Furthermore there is an optical fiber placed into a groove and attached to the substrate.
U.S. Pat. No. 5,875,205 and U.S. Pat. No. 6,271,049 describe an optoelectronic assembly having active optical components (i.e., a laser chip) and passive optical components (i.e., a lens) integrated onto a substrate.
None of these prior art methods teach how to accurately position and align optical fibers and other optical and electrical devices on a substrate. There is a need for an assembly and a method for accurately positioning and aligning of optical components such as fibers, optical waveguides, and semiconductor devices on a substrate. The invention further needs to compactly integrate optical and electrical passive and active structures within the same coupling platform. The invention further needs to provide means for optimising the assembly of a complete optoelectronic component, and not only one of its constituents. The invention also needs to make use of standard processes and materials currently used in the microelectronics and micro-electromechanical systems industries, allowing for large-scale manufacturing at reduced cost, while still improving the accuracy and repeatability of the assembly.